This invention relates to appliances used for floor cleaning and the like. More specifically, the present invention relates to a means for adjusting the disposition of a vacuum cleaner carriage relative to a floor surface.
Vacuum cleaners of the floor cleaning or upright type generally include a chassis having a nozzle on a lower surface of a front end thereof through which nozzle air is sucked by an air moving motor-blower unit. A rotary brush is mounted adjacent the nozzle for contacting the floor surface to agitate and loosen the dirt so that it may be sucked free of the surface. Wheels or other supports are rotatively mounted at the front and rear of the chassis for supporting the cleaner in a rolling manner on the floor. These vacuum cleaners are called upon to clean many different kinds of modern floor coverings varying in pile thickness from the short outdoor or patio type carpeting to the long deep shag type. In order to clean these various floor surfaces effectively, it is known to vary the vacuum cleaner's nozzle height to locate the nozzle at a proper level above the surface to provide the required suction for the particular type of floor covering or surface being cleaned and to position the brush at the proper height.
While many types of nozzle height adjusting mechanisms are known to the art, the known mechanisms are relatively complex and include a large number of parts because many nozzle heights are necessary to handle the different kinds of modern floor coverings available. The inherent multiplicity of such parts has made it more expensive to manufacture and assemble an upright vacuum cleaner.
There are also times when it is necessary to lift the rotating brush away from the floor surface while the vacuum cleaner continues to run. This occurs when the user leaves the vacuum cleaner at one location while using an off the floor cleaning attachment. If the brush were to be left on the floor surface in such a situation, it might cause excessive wear, on e.g. carpeting, at that location. Also, unnecessary strain on the motor might result.
Numerous lift off mechanisms have therefore been developed to move the rotating brush away from the floor surface when desired. Those mechanisms which are mechanically coupled to the movement of the vacuum cleaner's handle employ mechanically complicated linkages. Locking arrangements meant to keep the brush away from the floor surface while the handle is in the upright position add yet further complexity to the system.
Accordingly, it has been considered desirable to develop a new and improved vacuum cleaner height adjusting mechanism and nozzle lift off mechanism which are mechanically simple, compact, durable in nature and which overcome the foregoing difficulties and others while providing better and more advantageous overall results.